CALCULATIONS OF IMPURITIES MASS TRANSFER IN SODIUM-COOLED COLD TRAPS

Cold traps (CT) are heat and mass transfer devices used for the continuous cleaning of the circulating coolant there through. Currently proposed are two CT constructions built into the reactor vessel, cooled argon and sodium.
Sodium is used for cooling the different devices with high reliability for a long time (decades) and can be implemented to cool built into the reactor vessel CT.
Advantages of sodium cooling are that entering the primary circuit sodium it does not cause adverse effects. The sodium cooling provides a more economical use of the volume inside of the cold trap.
To improve the competitiveness of the built in vessel sodium-cooled CT, it is necessary to create a compact closed circulation system of the sodium coolant.
In order to obtain maximum CT capacity by the impurities the optimization of design and parameters of the cold trap is carried out. The main criterion of optimize is the uniformity of distribution of the impurity deposition on the length of the trap. Increasing of distribution unevenness leads to lower capacity of the trap by impurities.
To solve the complex problem of thermal-hydraulic and mass transfer in CT was used modified code OpenFOAM. The problem was solved in a stationary formulation by solution of the Navier-Stokes equations averaged Reynolds (URANS) by method SIMPLE. Completed calculations showed that OpenFOAM can calculation heat and mass transfer of impurities in the working cavity of the CT.
In the calculations by the code MASKA-LM is considered the influence of geometry changes of working cavity due to impurities deposition on surfaces. The proposed method of calculation allows us to estimate the capacity of the CT by impurities and the time to exhaustion of its resource.